1. Field of the Invention
The present invention relates generally to air-conditioning control apparatuses that control air conditioners and other cooling equipment. More particularly, the invention relates to an air-conditioning control apparatus that controls cooling equipment for a data center in which is installed an information-processing system that includes information-processing units such as server units and the cooling equipment that cools such information-processing units.
2. Description of the Related Art
Information-processing units such as server units have increased remarkably. For cooling of heat generated in such units, accordingly, electric power that cooling equipment consumes, i.e., electric power for cooling has also increased. This leads to a problem with overall power reduction in which electric power consumed by the information-processing units and electric power consumed for cooling of these units are considered totally.
Efforts associated with electric power saving in information-processing units, cooling equipment, and their operational management are made with a view towards saving electric power in data centers.
These efforts in information-processing units are being made by improving performance per power consumption by the use of lower-power devices, and by adopting a function that saves power by switching an operation state according to workload.
In cooling equipment, efforts are being made by improving the operating efficiency of the installed air conditioners, by optimizing the airflow design of air supply and exhaust ports, and by introducing local cooling or liquid cooling.
In terms of operational management, efforts are being undertaken primarily in the forms of operating state information monitoring, job scheduling, and the operating efficiency improvement and consolidation of hardware by virtualization.
Cooling equipment such as air conditioners is generally designed in accordance with a maximum total electric power rating of information-processing units. During actual equipment operation, however, not all of the information-processing units are used and loads of the information-processing units actually used do not always become a maximum, either.
With the future progress of the operational management technology for data centers, the consolidation of the information-processing units is expected to be further utilized by the use of virtualizing technology to save electric power.
To ensure electric power saving in a data center under such circumstances, it is effective to implement measures towards reduced overall electric power of cooling equipment allowing for the possible non-uniformity and hourly variations in a power distribution of information-processing units with respect to the cooling equipment.
Referring to the reduction in the overall electric power of the cooling equipment, there are several known operational management methods for the information-processing system that includes the information-processing units and the cooling equipment.
Firstly, in a management server that conducts job scheduling upon parallel computers is known a method for loading a new job into a computer with less heat (this indicates that the computer is not too heavily loaded) in accordance with computer temperature sensor information, next moving a job from a computer with high heat (this indicates that the computer is heavily loaded), into the lower-temperature computer, and thus preventing a failure in the parallel computers or a decrease in performance of these computers from resulting from high temperatures. This method is described in, for example, JP-2004-126968-A (referred to as Patent Document 1). In this method, whether the movement of the job can be executed is determined by estimating, from temperature information, the amount of electric power consumed by the corresponding computers before and after the movement of the job, and the amount of electric power consumed by cooling units provided for each computer.
Secondly, in a management system for a plurality of computers is known a method for selecting a computer of a relatively high temperature (a heavily loaded computer) and a computer of a relatively low temperature (a lightly loaded computer) in accordance with a temperature distribution of and operating state information about the computers, next moving software from the higher-temperature computer and the lower-temperature computer, and thus saving electric power. This method is described in, for example, JP-2007-179437-A (referred to as Patent Document 2). In this method, whether the movement of the software can be executed is determined by comparing variations in the amount of electric power consumed by the selected computers before and after the movement of the software, and in the amount of electric power consumed by air conditioners. The power consumption in the computers is calculated from operating state information, the power consumption in the air conditioners is calculated from the temperature distribution, and the temperature distribution is calculated from temperature sensor information, temperature histories, and the operating state information.
Thirdly, in a known method of allocating a workload to a plurality of servers present in a data center, a profile of a requested workload is compared with historical workload profiles, next the requested workload is allocated to the servers in accordance with a historical workload profile denoting the fact that the amount of electric power consumed by the servers and air conditioners is minimized, and if a matching history is absent, the workload is allocated in a random manner. This method is described in, for example, US Patent Application Serial No. 2006/0259621 (referred to as Patent Document 3). In this method, the historical workload profile contains server locations, classes, and operating state information, server intake air temperatures and exhaust air temperatures, workload types, and the amount of electric power consumed by the servers and the air conditioners. The amount of electric power consumed by the servers and the air conditioners is either calculated from the server intake air temperatures and exhaust air temperatures, specific heat, and the quantities of air, or measured by a wattmeter.
Fourthly, in a known method of distributing electric power to a plurality of servers present in a data center, the occurrence of server failures due to hot spots or cold spots can be prevented by lending and borrowing a power budget between geographically adjacent servers or racks so that the distribution of the power approaches an ideal analog-like temperature distribution, or power distribution, and specifying discretized power states of the servers according to the particular budget allocations. This method is described in, for example, US Patent Application Serial No. 2006/0259793 (referred to as Patent Document 4). In this method, thermal multipliers that denote ideal power for the servers are determined from exhaust air temperatures of the servers, a reference exhaust air temperature of an average server, and supply air temperatures of air conditioners.
Fifthly, there is a known method in which an air conditioner operating coefficient relating to information-processing units is calculated for air conditioners and a unit-related power consumption scheme is created for the information-processing units. This method is described in, for example, JP-2011-34578-A (referred to as Patent Document 5). In this method, a power-saving performance evaluation index based on the unit-related power consumption scheme for the information-processing units is used to determine workload allocations for power saving in the entire computer room. In this known method, a workload of the information-processing units is controlled in accordance with workload allocation results, power consumption in the air conditioners is calculated from the air conditioner operating coefficient and a measured value of power consumption in the information-processing units, and air conditioner output is controlled.